Backup Exec 12d problems

The remote agent loses connection with the backup server, causing backups to fail
The mail server intermittently takes a long time to finish a backup job (12+ hours intead of ½ hour), causing subsequent jobs to run over. This causes problems such as the file server backup failing, or the mail server missing its window and not running.
Open files will not backup, despite trying several open file options.
Backup Exec job engine occasionally hangs without notification, causing jobs to not run until the service is restarted.
Job notifications seem not to work correctly.

And are the clients updated too? updates for the server, often include new updates for the agents that need to be pushed out.

Outside of that, make sure no AV software is scanning the database files, or any of the backupexec directories for that matter on both server and clients.

After that, I'd also check your NIC settings and drivers. You'll want to find the article in the support KB about TCP offload, and turning that off. There are a number of recommendations in the KB article.

There is an online portal, save yourself the long hold times. Create ticket online, then call in with ticket # in hand :-) http://mysupport.symantec.com "We backup data to restore, we don't backup data just to back it up."